/**
 * Link to the project's GitHub page:
 * https://github.com/pickhardt/coffeescript-codemirror-mode
 */
CodeMirror.defineMode('coffeescript', function (conf) {
  var ERRORCLASS = 'error';

  function wordRegexp(words) {
    return new RegExp("^((" + words.join(")|(") + "))\\b");
  }

  var singleOperators = new RegExp("^[\\+\\-\\*/%&|\\^~<>!\?]");
  var singleDelimiters = new RegExp('^[\\(\\)\\[\\]\\{\\}@,:`=;\\.]');
  var doubleOperators = new RegExp("^((\->)|(\=>)|(\\+\\+)|(\\+\\=)|(\\-\\-)|(\\-\\=)|(\\*\\*)|(\\*\\=)|(\\/\\/)|(\\/\\=)|(==)|(!=)|(<=)|(>=)|(<>)|(<<)|(>>)|(//))");
  var doubleDelimiters = new RegExp("^((\\.\\.)|(\\+=)|(\\-=)|(\\*=)|(%=)|(/=)|(&=)|(\\|=)|(\\^=))");
  var tripleDelimiters = new RegExp("^((\\.\\.\\.)|(//=)|(>>=)|(<<=)|(\\*\\*=))");
  var identifiers = new RegExp("^[_A-Za-z][_A-Za-z0-9]*");

  var wordOperators = wordRegexp(['and', 'or', 'not',
    'is', 'isnt', 'in',
    'instanceof', 'typeof']);
  var indentKeywords = ['for', 'while', 'loop', 'if', 'unless', 'else',
    'switch', 'try', 'catch', 'finally', 'class'];
  var commonKeywords = ['break', 'by', 'continue', 'debugger', 'delete',
    'do', 'in', 'of', 'new', 'return', 'then',
    'this', 'throw', 'when', 'until'];

  var keywords = wordRegexp(indentKeywords.concat(commonKeywords));

  indentKeywords = wordRegexp(indentKeywords);


  var stringPrefixes = new RegExp("^('{3}|\"{3}|['\"])");
  var regexPrefixes = new RegExp("^(/{3}|/)");
  var commonConstants = ['Infinity', 'NaN', 'undefined', 'null', 'true', 'false', 'on', 'off', 'yes', 'no'];
  var constants = wordRegexp(commonConstants);

  // Tokenizers
  function tokenBase(stream, state) {
    // Handle scope changes
    if (stream.sol()) {
      var scopeOffset = state.scopes[0].offset;
      if (stream.eatSpace()) {
        var lineOffset = stream.indentation();
        if (lineOffset > scopeOffset) {
          return 'indent';
        } else if (lineOffset < scopeOffset) {
          return 'dedent';
        }
        return null;
      } else {
        if (scopeOffset > 0) {
          dedent(stream, state);
        }
      }
    }
    if (stream.eatSpace()) {
      return null;
    }

    var ch = stream.peek();

    // Handle comments
    if (ch === '#') {
      stream.skipToEnd();
      return 'comment';
    }

    // Handle number literals
    if (stream.match(/^-?[0-9\.]/, false)) {
      var floatLiteral = false;
      // Floats
      if (stream.match(/^-?\d*\.\d+(e[\+\-]?\d+)?/i)) {
        floatLiteral = true;
      }
      if (stream.match(/^-?\d+\.\d*/)) {
        floatLiteral = true;
      }
      if (stream.match(/^-?\.\d+/)) {
        floatLiteral = true;
      }
      if (floatLiteral) {
        return 'number';
      }
      // Integers
      var intLiteral = false;
      // Hex
      if (stream.match(/^-?0x[0-9a-f]+/i)) {
        intLiteral = true;
      }
      // Decimal
      if (stream.match(/^-?[1-9]\d*(e[\+\-]?\d+)?/)) {
        intLiteral = true;
      }
      // Zero by itself with no other piece of number.
      if (stream.match(/^-?0(?![\dx])/i)) {
        intLiteral = true;
      }
      if (intLiteral) {
        return 'number';
      }
    }

    // Handle strings
    if (stream.match(stringPrefixes)) {
      state.tokenize = tokenFactory(stream.current(), 'string');
      return state.tokenize(stream, state);
    }
    // Handle regex literals
    if (stream.match(regexPrefixes)) {
      if (stream.current() != '/' || stream.match(/^.*\//, false)) { // prevent highlight of division
        state.tokenize = tokenFactory(stream.current(), 'string-2');
        return state.tokenize(stream, state);
      } else {
        stream.backUp(1);
      }
    }

    // Handle operators and delimiters
    if (stream.match(tripleDelimiters) || stream.match(doubleDelimiters)) {
      return 'punctuation';
    }
    if (stream.match(doubleOperators)
      || stream.match(singleOperators)
      || stream.match(wordOperators)) {
      return 'operator';
    }
    if (stream.match(singleDelimiters)) {
      return 'punctuation';
    }

    if (stream.match(constants)) {
      return 'atom';
    }

    if (stream.match(keywords)) {
      return 'keyword';
    }

    if (stream.match(identifiers)) {
      return 'variable';
    }

    // Handle non-detected items
    stream.next();
    return ERRORCLASS;
  }

  function tokenFactory(delimiter, outclass) {
    var delim_re = new RegExp(delimiter);
    var singleline = delimiter.length == 1;

    return function tokenString(stream, state) {
      while (!stream.eol()) {
        stream.eatWhile(/[^'"\/\\]/);
        if (stream.eat('\\')) {
          stream.next();
          if (singleline && stream.eol()) {
            return outclass;
          }
        } else if (stream.match(delim_re)) {
          state.tokenize = tokenBase;
          return outclass;
        } else {
          stream.eat(/['"\/]/);
        }
      }
      if (singleline) {
        if (conf.mode.singleLineStringErrors) {
          outclass = ERRORCLASS
        } else {
          state.tokenize = tokenBase;
        }
      }
      return outclass;
    };
  }

  function indent(stream, state, type) {
    type = type || 'coffee';
    var indentUnit = 0;
    if (type === 'coffee') {
      for (var i = 0; i < state.scopes.length; i++) {
        if (state.scopes[i].type === 'coffee') {
          indentUnit = state.scopes[i].offset + conf.indentUnit;
          break;
        }
      }
    } else {
      indentUnit = stream.column() + stream.current().length;
    }
    state.scopes.unshift({
      offset:indentUnit,
      type:type
    });
  }

  function dedent(stream, state) {
    if (state.scopes.length == 1) return;
    if (state.scopes[0].type === 'coffee') {
      var _indent = stream.indentation();
      var _indent_index = -1;
      for (var i = 0; i < state.scopes.length; ++i) {
        if (_indent === state.scopes[i].offset) {
          _indent_index = i;
          break;
        }
      }
      if (_indent_index === -1) {
        return true;
      }
      while (state.scopes[0].offset !== _indent) {
        state.scopes.shift();
      }
      return false
    } else {
      state.scopes.shift();
      return false;
    }
  }

  function tokenLexer(stream, state) {
    var style = state.tokenize(stream, state);
    var current = stream.current();

    // Handle '.' connected identifiers
    if (current === '.') {
      style = state.tokenize(stream, state);
      current = stream.current();
      if (style === 'variable') {
        return 'variable';
      } else {
        return ERRORCLASS;
      }
    }

    // Handle properties
    if (current === '@') {
      style = state.tokenize(stream, state);
      current = stream.current();
      if (style === 'variable') {
        return 'variable-2';
      } else {
        return ERRORCLASS;
      }
    }

    // Handle scope changes.
    if (current === 'return') {
      state.dedent += 1;
    }
    if (((current === '->' || current === '=>') &&
      !state.lambda &&
      state.scopes[0].type == 'coffee' &&
      stream.peek() === '')
      || style === 'indent') {
      indent(stream, state);
    }
    var delimiter_index = '[({'.indexOf(current);
    if (delimiter_index !== -1) {
      indent(stream, state, '])}'.slice(delimiter_index, delimiter_index + 1));
    }
    if (indentKeywords.exec(current)) {
      indent(stream, state);
    }
    if (current == 'then') {
      dedent(stream, state);
    }


    if (style === 'dedent') {
      if (dedent(stream, state)) {
        return ERRORCLASS;
      }
    }
    delimiter_index = '])}'.indexOf(current);
    if (delimiter_index !== -1) {
      if (dedent(stream, state)) {
        return ERRORCLASS;
      }
    }
    if (state.dedent > 0 && stream.eol() && state.scopes[0].type == 'coffee') {
      if (state.scopes.length > 1) state.scopes.shift();
      state.dedent -= 1;
    }

    return style;
  }

  var external = {
    startState:function (basecolumn) {
      return {
        tokenize:tokenBase,
        scopes:[
          {offset:basecolumn || 0, type:'coffee'}
        ],
        lastToken:null,
        lambda:false,
        dedent:0
      };
    },

    token:function (stream, state) {
      var style = tokenLexer(stream, state);

      state.lastToken = {style:style, content:stream.current()};

      if (stream.eol() && stream.lambda) {
        state.lambda = false;
      }

      return style;
    },

    indent:function (state, textAfter) {
      if (state.tokenize != tokenBase) {
        return 0;
      }

      return state.scopes[0].offset;
    }

  };
  return external;
});

CodeMirror.defineMIME('text/x-coffeescript', 'coffeescript');
